/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.mapred;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.xml.sax.SAXException;
/**
* Maintains a hierarchy of pools.
*/
public class PoolManager {
public static final Log LOG = LogFactory.getLog(
"org.apache.hadoop.mapred.PoolManager");
/** Time to wait between checks of the allocation file */
public static final long ALLOC_RELOAD_INTERVAL = 10 * 1000;
/**
* Time to wait after the allocation has been modified before reloading it
* (this is done to prevent loading a file that hasn't been fully written).
*/
public static final long ALLOC_RELOAD_WAIT = 5 * 1000;
// Map and reduce minimum allocations for each pool
private Map<String, Integer> mapAllocs = new HashMap<String, Integer>();
private Map<String, Integer> reduceAllocs = new HashMap<String, Integer>();
// Sharing weights for each pool
private Map<String, Double> poolWeights = new HashMap<String, Double>();
// Max concurrent running jobs for each pool and for each user; in addition,
// for users that have no max specified, we use the userMaxJobsDefault.
private Map<String, Integer> poolMaxJobs = new HashMap<String, Integer>();
private Map<String, Integer> userMaxJobs = new HashMap<String, Integer>();
private int userMaxJobsDefault = Integer.MAX_VALUE;
private String allocFile; // Path to XML file containing allocations
private String poolNameProperty; // Jobconf property to use for determining a
// job's pool name (default: mapred.job.queue.name)
private Map<String, Pool> pools = new HashMap<String, Pool>();
private long lastReloadAttempt; // Last time we tried to reload the pools file
private long lastSuccessfulReload; // Last time we successfully reloaded pools
private boolean lastReloadAttemptFailed = false;
public PoolManager(Configuration conf) throws IOException, SAXException,
AllocationConfigurationException, ParserConfigurationException {
this.poolNameProperty = conf.get(
"mapred.fairscheduler.poolnameproperty", "user.name");
this.allocFile = conf.get("mapred.fairscheduler.allocation.file");
if (allocFile == null) {
LOG.warn("No mapred.fairscheduler.allocation.file given in jobconf - " +
"the fair scheduler will not use any queues.");
}
reloadAllocs();
lastSuccessfulReload = System.currentTimeMillis();
lastReloadAttempt = System.currentTimeMillis();
// Create the default pool so that it shows up in the web UI
getPool(Pool.DEFAULT_POOL_NAME);
}
/**
* Get a pool by name, creating it if necessary
*/
public synchronized Pool getPool(String name) {
Pool pool = pools.get(name);
if (pool == null) {
pool = new Pool(name);
pools.put(name, pool);
}
return pool;
}
/**
* Reload allocations file if it hasn't been loaded in a while
*/
public void reloadAllocsIfNecessary() {
long time = System.currentTimeMillis();
if (time > lastReloadAttempt + ALLOC_RELOAD_INTERVAL) {
lastReloadAttempt = time;
try {
File file = new File(allocFile);
long lastModified = file.lastModified();
if (lastModified > lastSuccessfulReload &&
time > lastModified + ALLOC_RELOAD_WAIT) {
reloadAllocs();
lastSuccessfulReload = time;
lastReloadAttemptFailed = false;
}
} catch (Exception e) {
// Throwing the error further out here won't help - the RPC thread
// will catch it and report it in a loop. Instead, just log it and
// hope somebody will notice from the log.
// We log the error only on the first failure so we don't fill up the
// JobTracker's log with these messages.
if (!lastReloadAttemptFailed) {
LOG.error("Failed to reload allocations file - " +
"will use existing allocations.", e);
}
lastReloadAttemptFailed = true;
}
}
}
/**
* Updates the allocation list from the allocation config file. This file is
* expected to be in the following whitespace-separated format:
*
* <code>
* poolName1 mapAlloc reduceAlloc
* poolName2 mapAlloc reduceAlloc
* ...
* </code>
*
* Blank lines and lines starting with # are ignored.
*
* @throws IOException if the config file cannot be read.
* @throws AllocationConfigurationException if allocations are invalid.
* @throws ParserConfigurationException if XML parser is misconfigured.
* @throws SAXException if config file is malformed.
*/
public void reloadAllocs() throws IOException, ParserConfigurationException,
SAXException, AllocationConfigurationException {
if (allocFile == null) return;
// Create some temporary hashmaps to hold the new allocs, and we only save
// them in our fields if we have parsed the entire allocs file successfully.
Map<String, Integer> mapAllocs = new HashMap<String, Integer>();
Map<String, Integer> reduceAllocs = new HashMap<String, Integer>();
Map<String, Integer> poolMaxJobs = new HashMap<String, Integer>();
Map<String, Integer> userMaxJobs = new HashMap<String, Integer>();
Map<String, Double> poolWeights = new HashMap<String, Double>();
int userMaxJobsDefault = Integer.MAX_VALUE;
// Remember all pool names so we can display them on web UI, etc.
List<String> poolNamesInAllocFile = new ArrayList<String>();
// Read and parse the allocations file.
DocumentBuilderFactory docBuilderFactory =
DocumentBuilderFactory.newInstance();
docBuilderFactory.setIgnoringComments(true);
DocumentBuilder builder = docBuilderFactory.newDocumentBuilder();
Document doc = builder.parse(new File(allocFile));
Element root = doc.getDocumentElement();
if (!"allocations".equals(root.getTagName()))
throw new AllocationConfigurationException("Bad allocations file: " +
"top-level element not <allocations>");
NodeList elements = root.getChildNodes();
for (int i = 0; i < elements.getLength(); i++) {
Node node = elements.item(i);
if (!(node instanceof Element))
continue;
Element element = (Element)node;
if ("pool".equals(element.getTagName())) {
String poolName = element.getAttribute("name");
poolNamesInAllocFile.add(poolName);
NodeList fields = element.getChildNodes();
for (int j = 0; j < fields.getLength(); j++) {
Node fieldNode = fields.item(j);
if (!(fieldNode instanceof Element))
continue;
Element field = (Element) fieldNode;
if ("minMaps".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
mapAllocs.put(poolName, val);
} else if ("minReduces".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
reduceAllocs.put(poolName, val);
} else if ("maxRunningJobs".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
poolMaxJobs.put(poolName, val);
} else if ("weight".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
double val = Double.parseDouble(text);
poolWeights.put(poolName, val);
}
}
} else if ("user".equals(element.getTagName())) {
String userName = element.getAttribute("name");
NodeList fields = element.getChildNodes();
for (int j = 0; j < fields.getLength(); j++) {
Node fieldNode = fields.item(j);
if (!(fieldNode instanceof Element))
continue;
Element field = (Element) fieldNode;
if ("maxRunningJobs".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
userMaxJobs.put(userName, val);
}
}
} else if ("userMaxJobsDefault".equals(element.getTagName())) {
String text = ((Text)element.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
userMaxJobsDefault = val;
} else {
LOG.warn("Bad element in allocations file: " + element.getTagName());
}
}
// Commit the reload; also create any pool defined in the alloc file
// if it does not already exist, so it can be displayed on the web UI.
synchronized(this) {
this.mapAllocs = mapAllocs;
this.reduceAllocs = reduceAllocs;
this.poolMaxJobs = poolMaxJobs;
this.userMaxJobs = userMaxJobs;
this.userMaxJobsDefault = userMaxJobsDefault;
this.poolWeights = poolWeights;
for (String name: poolNamesInAllocFile) {
getPool(name);
}
}
}
/**
* Get the allocation for a particular pool
*/
public int getAllocation(String pool, TaskType taskType) {
Map<String, Integer> allocationMap = (taskType == TaskType.MAP ?
mapAllocs : reduceAllocs);
Integer alloc = allocationMap.get(pool);
return (alloc == null ? 0 : alloc);
}
/**
* Add a job in the appropriate pool
*/
public synchronized void addJob(JobInProgress job) {
getPool(getPoolName(job)).addJob(job);
}
/**
* Remove a job
*/
public synchronized void removeJob(JobInProgress job) {
getPool(getPoolName(job)).removeJob(job);
}
/**
* Change the pool of a particular job
*/
public synchronized void setPool(JobInProgress job, String pool) {
removeJob(job);
job.getJobConf().set(poolNameProperty, pool);
addJob(job);
}
/**
* Get a collection of all pools
*/
public synchronized Collection<Pool> getPools() {
return pools.values();
}
/**
* Get the pool name for a JobInProgress from its configuration. This uses
* the "project" property in the jobconf by default, or the property set with
* "mapred.fairscheduler.poolnameproperty".
*/
public String getPoolName(JobInProgress job) {
JobConf conf = job.getJobConf();
return conf.get(poolNameProperty, Pool.DEFAULT_POOL_NAME).trim();
}
/**
* Get all pool names that have been seen either in the allocation file or in
* a MapReduce job.
*/
public synchronized Collection<String> getPoolNames() {
List<String> list = new ArrayList<String>();
for (Pool pool: getPools()) {
list.add(pool.getName());
}
Collections.sort(list);
return list;
}
public int getUserMaxJobs(String user) {
if (userMaxJobs.containsKey(user)) {
return userMaxJobs.get(user);
} else {
return userMaxJobsDefault;
}
}
public int getPoolMaxJobs(String pool) {
if (poolMaxJobs.containsKey(pool)) {
return poolMaxJobs.get(pool);
} else {
return Integer.MAX_VALUE;
}
}
public double getPoolWeight(String pool) {
if (poolWeights.containsKey(pool)) {
return poolWeights.get(pool);
} else {
return 1.0;
}
}
}
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